This is a servo-controlled valve assembly. Allowing you to open one line at a time by setting the servo to the desired angle. It was designed for use with a hydroponics irrigation system, but I've since used these little fellas for a handful of flow control tasks :) It was designed for a closed irrigation network with a peristaltic pump and squishy tubing. So it works similarly, by "pinching" the lines closed with ball bearings driven by the 'DrumCam' as I like to call it.

For detailed info and build instructions, check it out here.